Is lumbar facet joint tropism developmental or secondary to degeneration? An international, large-scale multicenter study by the AOSpine Asia Pacific Research Collaboration Consortium

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Critical values of facet joint angulation and tropism in the development of lumbar degenerative spondylolisthesis: an international, large-scale multicenter study by the AOSpine Asia Pacific Research Collaboration Consortium

published_or_final_versio

Is lumbar facet joint tropism developmental or secondary to remodeling changes? An international, large-scale multicenter study by the AOSAP collaboration consortium

Session: Free Papers Spine: Degenerative 1: abstract no. 40328INTRODUCTION: Facet joint tropism is asymmetry in orientation of the bilateral facets. Some studies have shown that tropism may increase the risk of disc degeneration and herniations, as well as degenerative spondylolisthesis (DS). It remains controversial whether FJT is a pre-existing developmental phenomena or secondary to progressive joint remodeling. The following study addressed the occurrence of FJT of the lower lumbar spine (i.e. L3-S1) in a degenerative spondylolisthesis patient model. METHODS: This was an international, multi-center cross-sectional study of 267 patients with single level DS recruited from 33 spine institutes in Asia Pacific. FJT (≥8 degrees asymmetry) was assessed on MRI from L3-S1 and in relation to the level of DS. Patient demographic were noted and assessed in relation to FJT of each lumbar segment. RESULTS: 65% were females (mean age of 63 years; mean BMI: 26 kg/m2). FJT was present in 31.3% to 50.6% of DS levels. FJT involved 33.3% to 58.8% of the one or two non-DS levels adjacent to the DS level. Patient demographics were not found to be significantly related to FJT at any level (p>0.05). CONCLUSION: To the authors’ knowledge, this is one of the largest studies conducted, in particular in an Asian population, addressing the “origins concept” of FJT. Although levels with DS were noted to have FJT, adjacent levels with no DS also exhibited tropism and were not related to age and other patient demographics. This study suggested that FJT may have a pre-disposed orientation

Lumbar facet joint orientation in degenerative spondylolisthesis: the role of ethnic variation in the Asia Pacific

Program schedule A020Scientific session: Deformity surger

Facet joint tropism and degenerative spondylolisthesis: a study from the AOSAP Research Collaboration

General Posters GP14

Facet Joint Tropism and Degenerative Spondylolisthesis—A Study from the AOSAP Research Collaboration

The abstract can be viewed at http://www.spineresearchforum.org/WFSR_2014_Thieme_AbstractBook_with_Cover.pdfConference theme: The Intervertebral Disc - from Degeneration to Therapeutic Motion PreservationShort Talk SessionIntroduction Degenerative spondylolisthesis (dSpl) is translation of the vertebral body in relation to adjacent levels, mainly attributed to degenerative changes of the intervertebral disc and facet joint complexes, and primarily occurs at L4-L5. Studies have suggested that more sagittal oriented facet joints at L4-L5 are associated with dSpl. However, the role of facet joint tropism (i.e., asymmetry between facet joint orientations) in L4-L5 dSpl remains inconclusive, in particular, in an Asian population and possibly attributed to nonstandardized definitions of tropism. As such, the following study addressed the role of facet joint tropism in relation to L4-L5 dSpl in the Asia Pacific region. Materials and Methods A multinational, multiethnic cross-sectional image-based study was performed in 34 institutions in the Asia Pacific region. Lateral standing radiographs and axial MRIs and/or CT scans were obtained for patients diagnosed with lumbar dSpl. Imaging assessment consisted of the following: magnitude of slip displacement, level of spondylolisthesis, and left/right L4- L5 facet joint angulations were noted on image assessment. Patients with single level dSpl were included. Patients were further stratified into those presenting with (Group A) or without (Group B) L4-L5 dSpl. Facet joint tropismwas defined as 7 degrees difference (Grogan et al 1997) between left and right facet joints and also assessed on receiver operating characteristics (ROC) curve analysis to identify critical values for multivariate analysis. Gender, age, weight/height (body mass index [BMI]), and ethnicity were also noted. Results The study included 351 patients (36.9% males and 63.1% females) with a mean age of 61.8 years (range: 24-90 years). The mean BMIwas 25.6 kg/m2 (range: 15.4-43.9 kg/m2). There were 267 patients (76.1%) in Group A and 84 individuals (23.9%) in Group B (control). Sex type (p ¼ 0.295) and BMI (p ¼ 0.227) did not significantly differ between groups, but elevated age was more pronounced with L4-L5 dSpl (p ¼ 0.001). There was a statistically significant difference between right and left L4-L5 facet joint angulations between Group A (right mean: 57.5 degrees; left mean: 55.4 degrees) and Group B (right mean: 48.4 degrees; left mean: 46.5 degrees) (p < 0.001). Based on facet joint tropism of 7 degrees difference between facet angulations, there was no statistically significant difference between groups. ROC analysis identified high sensitivity and specificity of facet joint angulation difference of 15 degrees or greater associated with dSpl. Based on ageadjusted multivariate analysis, facet joint tropism with a critical value of 15 degrees or greater angulation difference noted an odds ratio of 2.34 (95% CI: 1.17-4.67; p ¼ 0.016) associated with dSpl. Slippage was noted with increased facet joint tropism, but the effects could not be discerned. Conclusion Greater sagittal FJ orientationwas associated with dSpl, aswas joint tropism. A critical value of 15 degrees FJ angle difference produced a twofold increased likelihood of dSpl. Our study broadens the understanding of FJ morphology and its role in degenerative sagittal plane instability. Acknowledgments This study was funded by AOSpine Asia Pacific. Disclosure of Interest None declare

Is lumbar facet joint tropism development or secondary to remodeling changes? An international, large-scale multi-centre study by the APSAP collaboration consortium

Session - Free Papers Spine Degenerative 1: abstract no. 40328INTRODUCTION: Facet joint tropism is asymmetry in orientation of the bilateral facets. Some studies have shown that tropism may increase the risk of disc degeneration and herniations, as well as degenerative spondylolisthesis (DS). It remains controversial whether FJT is a pre-existing developmental phenomena or secondary to progressive joint remodeling. The following study addressed the occurrence of FJT of the lower lumbar spine (i.e. L3-S1) in a degenerative spondylolisthesis patient model. METHODS: This was an international, multi-center cross-sectional study of 267 patients with single level DS recruited from 33 spine institutes in Asia Pacific. FJT (≥8 degrees asymmetry) was assessed on MRI from L3-S1 and in relation to the level of DS. Patient demographic were noted and assessed in relation to FJT of each lumbar segment. RESULTS: 65% were females (mean age of 63 years; mean BMI: 26 kg/m2). FJT was present in 31.3% to 50.6% of DS levels. FJT involved 33.3% to 58.8% of the one or two non-DS levels adjacent to the DS level. Patient demographics were not found to be significantly related to FJT at any level (p>0.05). CONCLUSION: To the authors’ knowledge, this is one of the largest studies conducted, in particular in an Asian population, addressing the “origins concept” of FJT. Although levels with DS were noted to have FJT, adjacent levels with no DS also exhibited tropism and were not related to age and other patient demographics. This study suggested that FJT may have a pre-disposed orientation

An International Multicenter Study Assessing the Role of Ethnicity on Variation of Lumbar Facet Joint Orientation and the Occurrence of Degenerative Spondylolisthesis in Asia Pacific: A Study from the AOSpine Asia Pacific Research Collaboration Consortium

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